What frequency is monitored by the leading ship?

[jpnnngtn]

This problem here is rather tough (to me). Perhaps you can help:

Two ships are moving along a line due east. The trailing vessel has a speed of 64.0 km/h relative to a land based observation point, and the leading ship has a speed of 45.0 km/h relative to the same station. The two ships are in a region of the ocean where the current is moving uniformly due west at 10.0 km/h. The trailing ship transmits a sonar signal at a frequency of 1200 Hz. What frequency is monitored by the leading ship? (Use 1520 m/s as the speed of sound in the ocean)

 

[quantumdude]

Hi,

As per Forums policy, I need you to show me how you started and where you got stuck.

Thanks,

 

[arcnets]

Hi jpnnngtn,
you have probably already found out that the ships' speeds relative to the medium are 74 km/h and 55 km/h respectively. I think you should look up 'Doppler effect' in your script/book, and see where that gets you. If you are still stuck, then please tell us what the difficulty is.

 

[jpnnngtn]

I stayed up and solved this one last night. I think i just needed to take a break and come back to it later.